Asbestus paper



UNITED STATES PATENT ()FFICE.

SILYANUS. TINGLEY, OF BOSTON, MASSACHUSETTS.

ASBESTUS PAPER.

SPECIFICATION 'iorming part of Letters Patent No. 310,334, dated January 6, 1885.

Application filed August :25, 1884. (No model.) I

To all whom. it may concern:

Be it known that I, SILVANUS TINGLEY, of Boston, county of Suffolk, State of Massachusetts, have'invented an Improvement in Asbestus Paper, of which the following description, in connection with the accompanying drawing, is a specification, likeletters on the drawing representing like parts.

The object of my invention is to produce a paper upon which may be written or printed matter which it is desired shall appear plain and legible, even when the paper is exposed to extreme heat. By a series of experiments I havediscovered that such a paper may be produced by the employment ofa sheet of paper composed of asbestus fiber, the said sheet forming an indestructible body, and upon one or both sides thereof I apply a thin sheet of ordinary writingpaper coated with a salt of soda or other equivalent material, which, under the action ot extreme heat. will form a thin glaze which will combine with lhe asbestus body.

My invention consists, essentially, of paper composed of an asbestus body covered upon one or both -sides with a thin writing-paper coated or impregnated with a salt which will fuse and form a thin glaze when heated.

Referring to the drawing, a represents a sheet of paper composed of asbestus paper to constitute the body of the sheet to be produced; and b I) represent the sheets of writing paper, preferably ordinary glue-sized paper thinly coated with tungstate of soda or any equivalent'salt which will fuse and form a glaze when heated, the strength of the solution being substantially such as will be formed by dissolving the soda in water at ordinary temperature.

The thin coat of the salt may be applied by means of a brush or by a bath. The thin pa per, prepared as described, is then united with the asbestus body by means of a cement composed of or containing a silicate of soda, the said cement having preferably added to it a small portion of carbonate of lime to set the mixture. The body and one or more thin sheets may be applied or pressed together be tween rollers.

The ink employed for writing or printing upon the thin paper which forms the fine smooth face of the asbestos body is or may be of an ordinary ink containing nitrate of silver; but, instead, other solutions of metal may be employed.

\V hen my improved paper is subjected to a high heat, the thin paper which forms the surface is consumed or destroyed, leaving the metal or incombustible part of the ink which has penetrated or touched the thin paper plainly legible on the asbestus body.

I clai 1n- 1. As an improved article of manufacture, a paper composed of a body sheet of asbestus, and covered on one' or both sides with ordinary thin paper commonly employed to re ceive writing or printing, the said thin paper being coated with a salt, substantially as described, which will form a glaze when the paper is subjected to a high heat, substantially as set forth.

2. A sheet of paper composed of an asbestus body having a thin sheet of ordinary writingpaper cemented to it at one side, the cement used containing silicate of soda, the said thin paper being coated with tungsta-te of soda or its known equivalents, to operate substantially as described.

In testimony whereof Ihave signed my name to this specification in the prcsen cc of two subscribing witnesses.

SILVAN US TINGLEY.

XVitnesses:

G. W. GREGORY, W. H. SIGSTON. 

